GM Aurigae

GM Aurigae

A light curve for GM Aurigae, plotted from TESS data. [1] The 6.02 day period [2] is marked in red.
Observation data Epoch J2000       Equinox J2000
Constellation	Auriga
Right ascension	04h 55m 10.9816s [3]
Declination	+30° 21′ 59.374″ [3]
Apparent magnitude  (V)	12.24 [4]
Characteristics
Evolutionary stage	T Tauri star
Spectral type	K3Ve [4] or K6 [5]
Astrometry
Radial velocity (Rv)	14.9±0.3 [5] km/s
Proper motion (μ)	RA: +3.748 mas/yr [3] Dec.: −24.298 mas/yr [3]
Parallax (π)	6.3248±0.0490  mas [3]
Distance	516 ± 4  ly (158 ± 1  pc)
Details [5]
Mass	0.95±0.05  M☉
Radius	2.02±0.06  R☉
Luminosity	1.25±0.08  L☉
Surface gravity (log g)	3.80±0.03  cgs
Temperature	4287±35  K
Rotation	~6 days
Rotational velocity (v sin i)	13.5±0.2 km/s
Age	~1.5  Myr
Other designations
GM Aur, AAVSO 0448+30, TIC 96533063, GCRV 55585, IRAS 04519+3017, 2MASS J04551098+3021595, WISE J045510.97+302159.2, WISEA J045510.97+302159.1, 2E 1172, AKARI-IRC-V1 J0455110+302159, AP J04551098+3021595, CSI+30-04520 2, GEN# +6.20078077, HBC 77, HBHA 2713-04, MHA 259-1, PSCz P04519+3017, SVS 1089, UCAC4 602-015297 [4]
Database references
SIMBAD	data

GM Aurigae (GM Aur) is a K6V-type T Tauri star located 155 parsecs from Earth in the constellation of Auriga. It has a mass of 0.95 solar masses, a radius of 2 solar radii, a luminosity of 1.2 solar luminosity and a temperature of 4287 Kelvin. It has an age of around 3-10 million years ^[6] and is a member of the Taurus-Auriga star forming region. The star is host to a circumstellar disk with a possible planet still forming within it.

It has a stellar rotation period between 5.18 and 6.1 days, with a rotational period of approximately 6.04 days being most likely.

Circumstellar disk

GM Aur is host to an extensively studied circumstellar disk. Within this disk it has a large dust cavity located at 35 AU. There is a fainter disk extending up to 250 AU. ^[7] There is no consensus on whether this cavity was carved out by a forming exoplanet accreting material, photoevaporation, magnetohydrodynamic disk winds or a combination of all of the above. ^[5] If there were a planet forming in the system, it would likely have a minimum mass of about 1.10 Jupiter masses. ^[5] Spatially resolved submillimetre observations of GM Aur confirm the existence of a transitional disc that is inclined at 52.77° with respect to the line of sight. This disk also has an inner dust cavity with a radius of 30-40 AU. ^[5]

Spectra taken of the stars circumstellar disk show that H2 dominated the spectrum. Other than H2, OH lines have been detected within the disk of GM Aur along with CO emissions. Methyl cations (CH3) and bicarbonate (HCO) have also been found within the disk along with tentative signals of carbon dioxide. Water (H2O) has also been detected, but is photo-destroyed at a rate of around ${\displaystyle 5.4\times 10^{40}}$ molecules of water destroyed every second. This rate of destruction is less volatile than other stars. ^[8]

The GM Aurigae planetary system ^{[5] [a]}

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b(unconfirmed)	≥1.10±0.30 MJ	0.082±0.002	8.745±0.009	—	—	—

Magnetic field

The large-scale magnetic field of GM Aur has a dipolar configuration with a slight tilt. It has a strength of 730 gauss which is similar to other classical T Tauri stars with similar rotational periods. ^[5]

Notes

1. The circumstellar disk has an inclination of 52.77°±0.05° to the plane of the sky. If the planet shares that inclination, its true mass would be 1.38±0.37 M_J.

References

1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 13 November 2025.
2. "GM Aur". The International Variable Star Index. AAVSO. Retrieved 13 November 2025.
3. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
4. "V* GM Aur". SIMBAD . Centre de données astronomiques de Strasbourg.
5. Zaire, B.; Donati, J.-F.; Alencar, S. P.; Bouvier, J.; Moutou, C.; Bellotti, S.; Carmona, A.; Petit, P.; Kóspál, Á.; Shang, H.; Grankin, K.; Manara, C.; Alecian, E.; Gregory, S. P.; Fouqué, P. (13 August 2024). "Magnetic field, magnetospheric accretion, and candidate planet of the young star GM Aurigae observed with SPIRou". Monthly Notices of the Royal Astronomical Society. 533 (3): 2893–2915. arXiv: 2408.05864 . Bibcode:2024MNRAS.533.2893Z. doi: 10.1093/mnras/stae1955 . ISSN   0035-8711.
6. "★ GM Aurigae". Stellar Catalog. Retrieved 2025-09-30.
7. Macías, Enrique; Espaillat, Catherine C.; Ribas, Álvaro; Schwarz, Kamber R.; Anglada, Guillem; Osorio, Mayra; Carrasco-González, Carlos; Gómez, José F.; Robinson, Connor (2018). "Multiple Rings in the Transitional Disk of GM Aurigae Revealed by VLA and ALMA". The Astrophysical Journal. 865 (1): 37. arXiv: 1808.01920 . Bibcode:2018ApJ...865...37M. doi: 10.3847/1538-4357/aad811 . ISSN   0004-637X.
8. Romero-Mirza, Carlos E.; Öberg, Karin I.; Banzatti, Andrea; Tabone, Benoît; Najita, Joan; Blake, Geoffrey A.; Bergin, Edwin A.; Krijt, Sebastiaan; Law, Charles J.; Long, Feng; Huang, Jane; Wilner, David J.; Andrews, Sean M.; Czekala, Ian; Teague, Richard (2025-09-22). "JWST-MIRI Observations of the Irradiated Chemistry in the Inner Disk Cavity of GM Aur". The Astrophysical Journal. 991 (2): 128. Bibcode:2025ApJ...991..128R. doi: 10.3847/1538-4357/adf8db . ISSN   0004-637X.